Treatment of stenotic regions

ABSTRACT

An improved method and devices for preventing restenosis are provided. The method may include delivering a stent configured to contain a stenosis to a body vessel. The method may also include using atherectomy at the site prior to stent delivery. In one embodiment, the stent has a proximal end, a distal end, and a center portion arranged such that the diameters of the proximal and distal ends are greater than the diameter of the center portion. In one embodiment, the atherectomy device includes a housing to prevent injury to the unaffected areas of the body vessels but the cutter is extendible beyond the housing. In one embodiment, the stent may be impregnated with at least one drug after stent deployment.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to medical devices and, inparticular, to methods and devices of preventing restenosis.

[0003] 2. Description of the Related Art

[0004] Many causes of restenosis in angioplasty have been theorizedamong health care professionals. Many diseases cause body lumens toundergo stenosis or a narrowing of a canal within the body. Theresulting reduced blood flow can permanently damage tissue and organs.Stenotic regions that limit or obstruct coronary blood flow are a majorcause of ischemic heart disease related mortality.

[0005] The therapeutic alternatives generally used for treatment ofstenosis involve intervention (alone or in combination of therapeuticagents) to remove the blockage, replacement of the blocked segment witha new segment of artery, or the use of catheter-mounted devices such asa balloon catheter to dilate the artery. The dilation of an artery witha balloon catheter is called percutaneous transluminal angioplasty(PTA). A stent may also be delivered, as known in the art.

[0006] Often angioplasty permanently opens previously occluded bloodvessels; however, restenosis thrombosis, or vessel collapse may occurfollowing angioplasty. A major difficulty with PTA is the problem ofpost-angioplasty closure of the vessel, both immediately after PTA(acute reocclusion) and in the long term (restenosis).

[0007] Re-narrowing (restenosis) of an artery after angioplasty occursin 10-50% of patients undergoing this procedure and subsequentlyrequires either further angioplasty or other procedures. Restenosis(chronic reclosure) after angioplasty is a more gradual process thanacute reocclusion: 30% of patients with subtotal lesions and 50% ofpatients with chronic total lesions will go on to restenosis afterangioplasty. Because 30-50% of patients undergoing PTCA will experiencerestenosis, restenosis has limited the success of PTCA as a therapeuticapproach to coronary artery disease.

[0008] Recently, intravascular stents have been the focus of substantialattention as a means of preventing acute reclosure after PTA. Moststents are delivered to the desired implantation site percutaneously viaa catheter or similar transluminal device. Once at the treatment site,the compressed stent is expanded to fit within or expand the lumen ofthe passageway. Stents are typically either self-expanding or areexpanded by inflating a balloon that is positioned inside the compressedstent at the end of the catheter. Intravascular stents are oftendeployed after coronary angioplasty procedures to reduce complications,such as the collapse of arterial lining, associated with the procedure.

[0009] However, stents do not entirely reduce the occurrence ofthrombotic abrupt closure due to clotting; stents with rough surfacesexposed to blood flow may actually increase thrombosis, and restenosismay still occur because tissue may grow through and around the stent andthe lattice of the stent.

SUMMARY OF THE INVENTION

[0010] In accordance with one embodiment of the present invention,improved methods and devices for inhibiting and preventing restenosisare provided.

[0011] In one embodiment, a stent has a tubular body having a proximalend, a distal end, and a center portion, wherein the diameter of theproximal end and the diameter of the distal end are greater than thediameter of the center portion, such that the stent contains a stenosis.

[0012] In one embodiment, the distal end and proximal end each extendabout 1-6 mm beyond the stenosis. In another embodiment, the distal endand proximal end each extend about 5 mm beyond the stenosis. In anotherembodiment, the distal end and proximal end each extend at least lmmbeyond the stenosis. The stent may be self-expanding or balloonexpandable. In one embodiment, the stent includes at least one drug. Inone embodiment, the stent includes a plurality of drugs. The drug mayinclude a time-released drug. In one embodiment, the diameter of theproximal end is equal to the diameter of the distal end. In anotherembodiment, the diameter of the proximal end is greater than thediameter of the distal end. In another embodiment, the diameter of thedistal end is greater than the diameter of the proximal end.

[0013] In one embodiment, an atherectomy device having an axiallymovable cutting element and a tubular housing surrounding the cuttingelement to protect undamaged vessels from the cutting element isprovided.

[0014] In one embodiment, a catheter placement device having aguidewire, a bent tubular element, wherein the tubular element isadapted to be delivered over the guidewire and a balloon for stabilizingthe directional catheter at a bifurcated vessel is provided.

[0015] In one embodiment, a method of inhibiting restenosis is provided.The method includes performing atherectomy at a vessel site, anddelivering a stent to the site. The stent may have a tubular body havinga proximal end, a center portion, and a distal end, arranged such thatproximal end and distal end have a larger diameter than the centerportion, such that the stent contains a stenosis.

[0016] In one embodiment, a method of inhibiting restenosis is provided.The method includes delivering a stent to a treatment site, andimpregnating the stent with at least one drug at the treatment site. Thestent may be impregnated about 3-6 months after the stent is deliveredto the treatment site. In one embodiment, the delivering a stent andimpregnating the stent are performed with a substantial time between thetwo steps.

[0017] In one embodiment, a drug impregnation catheter having anelongate tubular body having a proximal end and a distal end, and aballoon attached to the distal end of the tubular body, wherein theballoon comprises a coating comprising at least one therapeutic agent isprovided.

[0018] The systems and methods have several features, no single one ofwhich is solely responsible for its desirable attributes. Withoutlimiting the scope as expressed by the claims that follow, its moreprominent features will now be discussed briefly. After considering thisdiscussion, and particularly after reading the section entitled“Detailed Description of the Preferred Embodiments” one will understandhow the features of the system and methods provide several advantagesover traditional systems and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a perspective view showing a catheter having a stent ofthe present invention.

[0020]FIG. 2 is a cross-sectional view showing the catheter of FIG. 1through line 2-2.

[0021]FIG. 3 is a detailed longitudinal-sectional view of the distal endof the catheter and stent of FIG. 1 through line 3-3.

[0022]FIG. 3A is a detailed longitudinal-sectional view of the distalend of the catheter and expanded stent of FIG. 1.

[0023]FIG. 4 is a perspective view showing an alternative embodiment ofa catheter having a stent of the present invention.

[0024]FIG. 5 is a cross-sectional view showing the catheter of FIG. 4through line 5-5.

[0025]FIG. 6 is a detailed longitudinal-sectional view of the distal endof the catheter and stent of FIG. 4 through line 6-6.

[0026]FIG. 7 is a perspective view of a stent in a deployed state inaccordance with one embodiment.

[0027]FIG. 8 is a side view of the stent of FIG. 7.

[0028]FIG. 8A is an alternative view of a stent in accordance with anembodiment of the present invention.

[0029]FIG. 9 is an end view of the stent of FIG. 7.

[0030]FIGS. 10A and B are schematic views of the stent being implantedin the body.

[0031]FIG. 10C is a schematic view of an alternative embodiment of animplanted stent.

[0032]FIG. 11 is a perspective view of a directional catheter inaccordance with one embodiment.

[0033]FIG. 12 is a schematic view of the directional catheter in thebody.

[0034]FIG. 13 is a perspective view of an atherectomy device inaccordance with one embodiment.

[0035]FIG. 14 is a detailed longitudinal-sectional side view of theatherectomy device of FIG. 13.

[0036]FIG. 15 is a detailed cross-sectional end view of the atherectomydevice of FIG. 13.

[0037]FIGS. 16A and B are schematic views of the atherectomy device ofFIG. 13.

[0038]FIG. 16C and D are schematic views of an alternative embodiment ofthe atherectomy device.

[0039]FIG. 17A is a perspective view showing a catheter having a balloonin accordance with an embodiment.

[0040]FIG. 17B is a detailed magnified view of the distal end of thecatheter and balloon of FIG. 17A through line 17B-17B.

[0041]FIGS. 18A and B are schematic views of the catheter of FIGS.17A-17B in use in the body.

[0042]FIG. 18C is a schematic view of an alternative embodiment of thecatheter depicted in FIGS. 17 and 18.

[0043]FIGS. 19-24 are schematic views of the methods in accordance withone embodiment.

[0044]FIG. 25 depicts a multi-balloon inspection catheter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] The devices are described with reference to the accompanyingfigures, wherein like numerals refer to like elements. The terminologyused in the description is not intended to be interpreted in any limitedor restrictive manner simply because it is being utilized in conjunctionwith a detailed description of certain specific embodiments.Furthermore, embodiments may include several novel features, no singleone of which is solely responsible for its desirable attributes or whichis essential to practicing the inventions herein described. The words inthe claims are presented to have the customary and ordinary meanings.

[0046] Methods and devices for inhibiting restenosis are disclosed. Astent delivery catheter system in which a stent is deliveredintraluminally into a body lumen, such as a coronary artery, carotidartery, renal arteries, peripheral arteries and veins, and the like isalso disclosed. The catheter system is also useful in the brain, theurethral system and the vascular system.

Stent Delivery Device

[0047] A stent delivery catheter 100 is shown in FIG. 1. Deliverycatheter 100 preferably includes an elongate, flexible tubular shaft104, having a proximal end 106 and a distal end 108. The shaft 104defines one or more passages or lumens extending through the shaft.

[0048] Catheter 100 preferably comprises a balloon 114, having aproximal end 116 and a distal end 118. Elongate shaft 104 preferablyincludes a guide wire 122, extending from distal end 116 throughproximal end 106 of shaft 104, providing rigidity to device 100.Catheter 100 also includes a manifold 124. Manifold 124 preferablyincludes a guide wire port 126 and an inflation port 128. Catheter 100may also include radiopaque markers 129 to view the location of catheter100 within the patient's body lumen. Catheter 100 may also include asoft, flexible distal tip 121. Such catheters are known.

[0049]FIG. 2 shows a cross-sectional view of the elongate shaft 104,showing inner sleeve 110 and outer sleeve 112. The inner sleeve 110defines a guide wire lumen 130, while the inflation lumen 132 is definedby the annular space between the inner sleeve 110 and outer sleeve 112.The guide wire lumen 130 is adapted to receive an elongate guide wire122 in a sliding fashion through proximal guide wire port 126 incatheter manifold 124. The particular position and arrangement of lumensis merely exemplary.

[0050] Preferably, inflation lumen 132 is coupled to the balloon 114 toselectively inflate it with the inflating fluid. The inflation lumen 132provides fluid communication between the interior of the balloon 114 atthe distal end of the inflation lumen 132 and the inflation port 128located at manifold 124.

[0051] The inflation lumen 132 may also be adapted to hook up to avacuum, to eliminate air bubbles. Alternatively, a separate lumen may beprovided for connection with the vacuum. Vacuum lumen would also be incommunication with the internal cavity of balloon 114.

[0052] The catheter shaft 104 may have various configurations other thanthe coaxial design shown in the drawings, including a single extrudedmulti-lumen tube defining any suitable number of colinear, parallel orradially aligned lumens.

[0053] The stent 134 depicted in FIG. 1 is preferably removably carriedby the distal end 108 of elongate shaft 104. Stent 134 has an initialdiameter at which it is inserted into a body lumen, and an expandedfinal diameter. Stent 134, as shown in FIGS. 1, 3 and 3A, is aballoon-expandable slotted metal tube (usually but not limited tostainless steel or the like), which when expanded within the lumen,provides structural support to the arterial wall. Stent 134 comprises atubular structure. Although stent 134 is illustratively shown in theconfiguration 100 of FIG. 1, the stent 100 may be of virtually anyconfiguration so long as stent 100 meets the needs of the treatmentprocedures. Configurations, such as helices, coils, braids, expandabletube stents, roving wire stents, and wire mesh stents or the like may beutilized depending on the application for the device.

[0054] The balloon 114 may comprise a substantially inelastic, compliantmaterial. Many balloon configurations are known. The balloon 114 isformed from any suitable biocompatible material. The balloon 114 ispreferably removably attached to the catheter shaft 104 by affixing itsdistal end to the inner sleeve 110, and its proximal end to the outersleeve 112. The balloon 114 thereby communicates with the annularinflation lumen 132 between the inner sleeve 110 and outer sleeve 112.The balloon 114 may alternatively be attached to the shaft 104 in anyway that allows it to be inflated with fluid from the inflation lumen132.

[0055] The catheter manifold 124 provides a maneuvering handle for thehealth care professional, as well as an inflation port 128 and a guidewire port 126. Either or both the inflation port 128 or the guide wireport 126 may have a coupling, accompanied by a luer-lock fitting forconnecting an inflation lumen to a source of pressurized fluid in aconventional manner. The manifold 124 may also include an injection portfor allowing radiopaque contrast fluid to be injected through the outersleeve and around the catheter shaft, thus illuminating the deliverydevice on a fluoroscope. The proximal manifold 124 is preferablyinjection molded of any suitable material. A precision gasket may alsobe provided, which seals securely around the device, prohibiting fluidloss. Many other catheter configurations are also known.

[0056]FIG. 3A illustrates stent 134 in an expanded configuration beingdeployed by the balloon 114. Stent 134 is expanded by inflating balloon114. The balloon is preferably configured to expand stent 134 into thedesired configuration. As shown in FIG. 3A, the balloon 114 ispreferably configured to have a larger diameter at the proximal end 116and distal end 138 of the stent, while having a relatively smallerdiameter at the center of the stent.

[0057] The size of stent 134 varies, depending on the particulartreatment and access site. The overall length, diameter and wallthickness may vary based on the treatment. In a preferred embodiment,stent 134 has an inflated length between about 1 and 10 cm, preferablyabout 3-5 cm. In a preferred embodiment, stent 134 has an inflateddiameter between about 0.1 and 1.5 cm. However, stents of any suitabledimension for the application may be used.

[0058] One alternative embodiment of a stent delivery catheter isdepicted in FIG. 4 for delivery of self-expanding stents. Deliverycatheter 400 preferably includes an elongate, flexible tubular shaft404, having a proximal end 406 and a distal end 408. The shaft 404defines one or more passages or lumens extending through the shaft.

[0059] An inner member 410 and an outer member 412 are preferablyarranged in coaxial alignment, as shown in FIG. 5. Member 412 forms aninner lumen 414. Inner member 410 is slidably positioned within innerlumen 414 of outer member 412 and relative axial movement between thetwo members is provided by inner member control handle 424 and outermember control handle 426 (see FIG. 4).

[0060] A self-expanding stent 434, as shown in FIG. 6 is mounted withinthe distal end 408 of catheter 400. Stent 434 comprises a tubularstructure, having an inner lumen 436. Self-expanding stent 434 can takevirtually any configuration self-explanding stent. Configurations, suchas helices, coils, braids, expandable tube stents, roving wire stents,and wire mesh stents or the like may be utilized depending on theapplication for the device.

[0061] The self-expanding stent 434 is inserted in outer member innerlumen 414 and positioned at the outer member distal end. In thoseinstances where self-expanding stent 434 is made from a material that isbiased outwardly, stent 434 will be compressed and inserted into innerlumen 414. Thereafter, the distal end of inner member 410 is positionedwithin stent inner lumen 436 so that the outer surface of inner member410 can come into contact with the stent inner lumen 436.

[0062] Inner member 410 is preferably made from a polymeric materialthat either is soft by design, or will become soft when heat is applied.The intent is to removably attach self-expanding stent 434 on the outersurface of inner member 410. Inner member 410 will partially fill theopen lattice structure of stent 434 so that the stent 434 cannot move inan axial direction along the outer surface of inner member 410.

[0063] Self-expanding stent 434 is mounted on outer surface at thedistal end of inner member 410. Due to the coaxial arrangement betweeninner member 410 and outer member 412, the inner lumen 414 of outermember 412 covers self-expanding stent 434 and helps to retain the stenton the outer surface of the inner member 410. The size of stent 434varies, depending on the particular treatment and access site, asdescribed above for balloon expanded stents

[0064] A guide wire lumen 430 which preferably extends through thecatheter is configured to receive guide wire 422. In order to implantself-expanding stent 434, guide wire 422 is positioned in a patient'sbody lumen, and typically guide wire 422 extends past a stenotic region.Distal end 408 is threaded over the proximal end of the guide wire whichis outside the patient and catheter 400 is advanced along the guide wireuntil distal end 408 of catheter 400 is positioned within the stenosedregion.

[0065] A stiffening mandrill may be incorporated in the proximal regionof catheter 400 to enhance the pushability of the catheter through thepatient's vascular system, and to improve the trackability of thecatheter over the guide wire, as known in the art. Preferably, Catheters100, 400 may be used to implant the stent in a body lumen using anover-the-wire or rapid-exchange catheter configuration. Over-the-wirecatheters are known in the art and details of the construction and useare set forth in U.S. Pat. Nos. 5,242,399, 4,468,224, and 4,545,390,which are herein incorporated by reference. Rapid-exchange catheters arealso known in the art and details of the construction and use are setforth in U.S. Pat. Nos. 5,458,613; 5,346,505; and 5,300,085, which areincorporated herein by reference.

[0066] Catheter manufacturing techniques are generally known in the art.The disclosed catheter is preferably made in a conventional manner.Stent

[0067] Stents 134 and 434 are shown in FIG. 7-9 in the expanded state.The stents 134, 434 have a center portion 450, a proximal end 452, and adistal end 454. The proximal end 452 and distal end 454 are curvedoutwards with respect to the center portion 450, as shown in FIGS. 7-9.Accordingly, the diameter at the proximal end 452 and distal end 454 aregreater than the diameter at the center portion 450 when the stent isexpanded. In some embodiments, the diameter at the proximal end 452 anddistal end 454 are equal. In other embodiments, the diameter at theproximal end 452 is larger than the diameter at the distal end 454, orvice versa. The actual rate of taper between the proximal end 452,distal end 454 and center portion 450 may vary depending on theparticular application.

[0068]FIG. 8A shows an alternative embodiment of a stent having theconfiguration shown in FIGS. 7-9. The stent 134, 434 of FIG. 8 may be atubular member 456 having a porous structure or having holes 458. Thetubular member 456 may be a graft material or other similarbiocompatible materials.

[0069]FIG. 10A shows a body vessel 460 having a stenosis 462. FIG. 10Bshows the stents 134, 434 implanted in the body vessel 460. The stent134, 434 extends beyond the plaque or stenosis 462 to contain thestenosis between the proximal end 452 and distal end 454 of the stent.In one embodiment, a pocket 464 is left between the vessel 460 and stent134, 434. In some embodiments, the stent 134, 434 extends about 1-6 mm,and more preferably 3-5 mm, beyond the plaque or stenosis 462 on eachside of the stenosis, thereby containing growth and preventing spilloverof the plaque. The actual dimensions of the stent and pocket may varydepending on the location of and degree of disease at the treatmentsite.

[0070]FIG. 10C shows the stent 134, 434 implanted in the body such thata pocket 464 is not left between the vessel 460 and stent 134, 434.Rather, the stent is expanded to conform to the stenosis. Theconfiguration shown in FIG. 10C similarly contains growth and preventsspillover of plaque, by extending beyond the stenosis 462.

[0071] For the expandable stent 134, the balloon 114 is shaped such thatit deploys in the configuration wherein the diameter at the proximal anddistal ends 452, 454 are greater than the diameter at the center portion450. For the self-expanding stent 434, the stent 434 is biased to expandin that same configuration. A number of different types of stentsincluding balloon-expanding, self-expanding, tubular graft stents andany other type of stent that can take on the shapes depicted may beused.

[0072] Balloon-expanding stents such as the well-known Palmaz-Schatzballoon expandable stent, are designed to be expanded and deployed byexpanding a balloon. Various kinds and types of stents are available inthe market, and many different currently available stents are acceptablefor use in the present invention, as well as new stents which may bedeveloped in the future. The stent can be a cylindrical metal mesh stenthaving an initial crimped outer diameter, which may be forcibly expandedby the balloon to the deployed varied diameter. When deployed in a bodypassageway of a patient, the stent may be designed to preferably pressradially outward to hold the passageway open.

[0073] Many balloon expandable stents are known in the art includingplastic and metal stents, such as the stainless steel stent shown inU.S. Pat. No. 4,735,665; the wire stent shown in U.S. Pat. No.4,950,227; another metal stent shown in European Patent Application EP0707 837 A1 and that shown in U.S. Pat. Nos. 5,445,646, or 5,242,451, thedisclosures of which are incorporated herein by reference.

[0074] Self-expanding stents such as that described in U.S. Pat. No.4,655,771 to Wallsten, incorporated herein by reference, expand from acontracted condition where they are mounted on the catheter assembly, toan expanded condition where the stent comes in contact with the bodylumen. The stents are self-expanding, which can be achieved by severalmeans. The stents are preferably formed from a stainless steel materialand are configured so that they are biased radially outwardly and expandoutwardly unless restrained. The stents also can be formed from a heatsensitive material, such as nickel titanium, which will self-expandradially outwardly upon application of a transformation temperature.These stents are representative of a large number of stents which can beadapted to the configuration illustrated in FIG. 7-9.

[0075] Tubular graft stents include a tubular graft attached to a stent.The tubular graft may be a biocompatible porous or nonporous tubularstructure to which a stent structure, such as a wire mesh, may beattached. The stent structure may be biased to assume an enlargedconfiguration corresponding to a target treatment site, but may beconstrained in a contracted condition to facilitate introduction into apatient's vasculature. The tubular graft preferably a peripheral walldefining a periphery and a lumen therein, the lumen extending betweenthe first and second ends of the tubular graft. The tubular graft may beprovided from a polymeric material, such as polyester,polytetrafluorethaline, Dacron, Teflon, and polyurethane. The stent maybe attached to the tubular graft by sutures, staples, wires, or anadhesive, or alternatively by thermal bonding, chemical bonding, andultrasonic bonding. The stent is preferably formed from a metallicmaterial, such as stainless steel or Nitinol, and may be a flat-coiledsheet with one or more serpentine elements formed therein, or a wireformed into a serpentine shape. The stent may be attached to an exteriorsurface of the tubular graft, to an interior surface of the tubulargraft, or embedded in the wall of the tubular graft. The stentpreferably is provided along the entire length of the graft. However, itis also envisioned that the stent may extend over a portion of thetubular graft. Alternatively, the graft may cover only a portion of thestent.

[0076] Configurations, such as helices, coils, braids, expandable tubestents, roving wire stents, and wire mesh stents or the like may beutilized with any of the above-described stents depending on theapplication for the device.

[0077] The stents as described herein can be formed from any number ofmaterials, including metals, metal alloys and polymeric materials.Preferably, the stents are formed from metal alloys such as stainlesssteel, tantalum, or the so-called heat sensitive metal alloys such asnickel titanium (NiTi). The stent may be made of any suitablebiocompatible material such as a metallic material or an alloy, examplesof which include, but are not limited to, stainless steel, elastinite(Nitinol), tantalum, nickel-titanium alloy, platinum-iriidium alloy,gold, magnesium, or combinations thereof. Alloys of cobalt, nickel,chromium, and molybdenum may also be used. The stents may also be madefrom bioabsorbable or biostable polymers. Stents formed from stainlesssteel or similar alloys typically are designed, such as in a helicalcoil or the like, so that they are spring biased outwardly.

[0078] With respect to stents formed from shape-memory alloys such asNiTi, the stent will remain passive in its martensitic state when it iskept at a temperature below the transition temperature. In this case,the transition temperature will be below normal body temperature, orabout 98.6° F. When the NiTi stent is exposed to normal bodytemperature, it will immediately attempt to return to its austeniticstate, and will rapidly expand radially outwardly to achieve itspreformed state. Details relating to the properties of devices made fromnickel-titanium can be found in “Shape-Memory Alloys,” ScientificAmerican, Vol. 281, pages 74-82 (November 1979), which is incorporatedherein by reference.

[0079] The pattern of the stent can be cut from either a cylindricaltube of the stent material or from a flat piece of the stent material,which is then rolled and joined to form the stent. Methods of cuttingthe lattice pattern into the stent material include laser cutting andchemical etching, as described in U.S. Pat. No. 5,759,192 issued toSaunders and U.S. Pat. No. 5,421,955 issued to Lau, both patentsincorporated herein by reference in their entirety. Alternativeembodiments, as known to those of skill in the art, of manufacturingstents may also be used. The stents may also be polished, as known tothose of skill of the art.

[0080] Furthermore, the stent can be coated with a drug or combinationof drugs to prevent proliferation. In a preferred embodiment, the stentsof the present invention are used to deliver more than one drug to adesired body location. Thus, treatment for different causes may beadministered with a combination of drugs. In addition, more than onedrug may be used for the same cause of restenosis, such that a reduceddosage may be administered, with lower risk of side-effects, and/or amore effective treatment of the cause. In addition, more than one drugmay be administered for multiple causes of restenosis. Both long termtherapies and short term therapies may be utilized. As used in thisapplication, the term “drug” denotes any compound which has a desiredpharmacological effect, or which is used for diagnostic purposes. Usefuldrugs include, but are not limited to angiogenic drugs, smooth musclecell inhibitors, collagen inhibitors, vasodilators, anti-plateletsubstances, anti-thrombotic substances, anti-coagulants, gene therapies,cholesterol reducing agents and combinations thereof. The drugs may alsoinclude, but are not limited to anti-inflammatory, anti-proliferative,anti-allergic, calcium antagonists, thromboxane inhibitors, prostacyclinmimetics, platelet membrane receptor blockers, thrombin inhibitors andangiotensin converting enzyme inhibitors, antineoplastic, antimitotic,antifibrin, antibiotic, and antioxidant substances as well ascombinations thereof, and the like.

[0081] Examples of these drugs include heparin, a heparin derivative oranalog, heparin fragments, colchicine, agiotensin converting enzymeinhibitors, aspirin, goat-anti-rabbit PDGF antibody, terbinafine,trapidil, interferongamma, steroids, ionizing radiation, fusiontonixins, antisense oligonucleotides, gene vectors (and other genetherapies), rapamycin, cortisone, taxol, carbide, and any other suchdrug. Examples of such antineoplastics and/or antimitotics includepaclitaxel, docetaxel, methotrexate, azathioprine, vincristine,vinblastine, fluorouracil, doxorubicin hydrochloride, and mitomycin.Examples of such antiplatelets, anticoagulants, antifibrin, andantithrombins include sodium heparin, low molecular weight heparins,heparinoids, hirudin, argatroban, forskolin, vapiprost, prostacyclin andprostacyclin analogues, dextran, D-phe-pro-arg-chloromethylketone(synthetic antithrombin), dipyridamole, glycoprotein IIb/IIIa plateletmembrane receptor antagonist antibody, recombinant hirudin, and thrombininhibitors such as Angiomax. Examples of such cytostatic orantiproliferative agents include angiopeptin, angiotensin convertingenzyme inhibitors such as captopril, cilazapril or lisinopril; calciumchannel blockers (such as nifedipine), colchicine, fibroblast growthfactor (FGF) antagonists, fish oil (omega 3-fatty acid), histamineantagonists, lovastatin (an inhibitor of antifibrin, and antithrombinsinclude sodium heparin, low molecular weight heparins, heparinoids,hirudin, argatroban, forskolin, vapiprost, prostacyclin and prostacyclinanalogues, dextran, D-phe-pro-arg-chloromethylketone (syntheticantithrombin), dipyridamole, glycoprotein IIb/IIIa platelet membranereceptor antagonist antibody, recombinant hirudin, and thrombininhibitors such as Angiomax.

[0082] Examples of such cytostatic or antiproliferative agents includeangiopeptin, angiotensin converting enzyme inhibitors such as captopril,cilazapril or lisinopril; calcium channel blockers (such as nifedipine),colchicine, fibroblast growth factor (FGF) antagonists, fish oil (omega3-fatty acid), histamine antagonists, lovastatin (an inhibitor ofHMG-CoA reductase, a cholesterol lowering drug), monoclonal antibodies(such as those specific for Platelet-Derived Growth Factor (PDGF)receptors), nitroprusside, phosphodiesterase inhibitors, prostaglandininhibitors, suramin, seratonin blockers, steroids, thioproteaseinhibitors, triazolopyrimidine (a PDGF antagonist), and nitric oxide.

[0083] An example of an antiallergenic agent is permirolast potassium.Other therapeutic substances or agents that may be used includealpha-interferon, genetically engineered epithelial cells, anddexamethasone. In other examples, the therapeutic substance is aradioactive isotope for prosthesis usage in radiotherapeutic procedures.Examples of radioactive isotopes include, but are not limited to,phosphoric acid, palladium, cesium, and iodine. While the preventativeand treatment properties of the foregoing therapeutic substances oragents are well-known to those of ordinary skill in the art, thesubstances or agents are provided by way of example and are not meant tobe limiting. Other therapeutic substances are applicable.

[0084] The therapeutic agent may also be provided with apharmaceutically acceptable carrier and, optionally, additionalingredients such as antioxidants, stabilizing agents, permeationenhancers, and the like. The drugs may also include radiochemicals toirradiate and/or prohibit tissue growth or to permit diagnostic imagingof a site.

[0085] Pits, pores, grooves, coatings, impregnateable materials, or acombination of these may be used to provide the drugs on the stent. Inaddition, a stent may include reservoirs or micropores to deliver drugsto the treatment site. Alternatively, the stent may include protrudingstructures which may have a central depression which may contain atherapeutic substance. Protruding structures are disclosed in U.S. Pat.No. 6,254,632, the disclosure of which is hereby incorporated byreference. These pits, pores, grooves, reservoirs, and protrudingstructures may be of any shape and size which may permit adequate drugdelivery to the treatment site.

[0086] In an alternative embodiment, the stent may comprise a pluralityof microencapsulated spheres containing a medicament, themicroencapsulated spheres being disposed about the exterior surface ofthe stent so as to rupture upon radial expansion of the stent by apredetermined amount. The microencapsulated spheres are preferablyencapsulated in a coating applied to the exterior surface of the stent.The spheres are preferably made from a bioabsorbable or biostablematerial.

[0087] In yet another embodiment, the stent may be coated with or haveas part of construction a collagen sponge (and possibly associatedanchor material). Collagen sponges, and associate anchor materials, areknown for use with other treatment modalities, such as to close wounds.In this embodiment, the collagen sponge carries the therapeutic agent,and releases the agent slowly over a period of days. Release of agentsover 30-90 days may be beneficial. For example, Cyclosporins are nowused in stents, but the agent is depleted in about 60 days. By using acollagen sponge as a coating or part of the stent, the Cyclosporin maycontinue to be delivered by the sponge for more than 60 days. Thisminimizes tissue reaction.

[0088] In one embodiment, the therapeutic agent may be located only onthe outer surface of the stent, such that the stenosis 460 is exposed tothe therapeutic agent (see FIG. 10B). By limiting the regions which areexposed to the therapeutic agent to the affected vessel site, sideeffects commonly associated with drug treatments may be reduced.Furthermore, the stent may include a therapeutic agent or combination oftherapeutic agents which can provide for long-term drug delivery at thevessel site.

[0089] Although a number of methods for applying drugs to a stent havebeen discussed, additional methods of incorporating drugs with a stentare known in the art and may be used.

Directional Catheter

[0090] Often vessels are injured while the guidewire is manuallymanipulated. In particular, doctors often have a difficult timemanipulating a guidewire into a smaller or tortuous branch of abifurcated vessel. Accordingly, a device is needed which protects thevessel and guides the guidewire into smaller vessels without furtherinjuring the patient.

[0091] In accordance with another embodiment, a directional guidecatheter 500 is provided for use with a guidewire delivery system, asshown in FIG. 11. The directional guide catheter 500 includes a tubularbody 502 having a proximal end 504 and a distal end 506. The tubularbody 502 preferably has an outer radius forming an outer bend 508, suchthat an axis x passing through the proximal end 504 and an axis ypassing through the distal end 506 are arranged at an angle θ,corresponding to the angle between the bifurcated vessels. Thedirectional catheter 500 can come in a variety of different sizes, inaccordance with the various vessels in the body. The diameters of thetubular body 502 at the proximal end 504 and the distal end 506 mayvary. The diameter at the distal end 506 may be the same size as thesmaller portion of the bifurcated vessel. The diameter at the proximalend 504 may be substantially the same size as the larger portion of thebifurcated vessel. Alternatively, the diameter at the proximal end 504and the diameter at the distal end 506 may be the same size.

[0092] The tubular body of the directional catheter is preferablyextruded. The tubular body is preferably made of a polymer such asNylon, the stiffness of which may be selected as apropriate. Materialselection varies based on the desired characteristics.

[0093] In use, the directional guide catheter 500 is delivered to abifurcation site 510, as shown in FIG. 12. The directional guidecatheter 500 may initially slide over a guidewire 512, and then directsthe guidewire 512 from a larger vessel 514 to a smaller vessel 516. Thedirectional guide catheter 500 lines the guidewire up so that it caneasily access the smaller vessel 516 without injuring the vessels at thebifurcation site 510. As shown in FIG. 12, the diameter at the distalend 506 of the tubular body 502 is substantially the same dimensions asthe smaller vessel 516. Similarly, the proximal end 504 of the tubularbody 502 is substantially the same dimensions as the larger vessel 514.

[0094] The directional guide catheter 500 may include a balloon 520 tosecure and stabilize the directional guide catheter 500 at thebifurcation site 510. The directional guide catheter 500 and balloon 520preferably permit the blood supply to continue through prefusiontechniques as known in the art. The directional catheter 500 may beremoved once the guide is positioned, before additional procedures areperformed.

[0095] Advantageously, the curved portion 516 of the directional guidecatheter 500 is constructed of a slightly higher durometer materials, sothat the guidewire 512 is more easily directed along the curve. Inaddition, preferably, a guiding tip 518, is configured of radiopaquematerial in order to be property viewed for location in the artery.

Atherectomy Device

[0096] In accordance with another embodiment, an improved atherectomydevice is shown in FIG. 13. In some embodiments, the diseased vesselportions and/or plaque may be cut out prior to implanting a stent at thesite, thereby preventing or reducing a restenosis. Current atherectomydevices are known to often damage non-diseased vessel portions. Anatherectomy device having a cutting element and protective housing isdisclosed. The housing is a shield for protecting the non-diseasedvessel portions, but the cutter is extendable from the housing fortreatment.

[0097] With reference to FIG. 13, atherectomy device 600 includes anelongate flexible tubular body 602 having a proximal end 604 and adistal end 606. A control 608 is preferably provided at or near theproximal end 604 of the tubular body 602 for permitting manipulation ofthe atherectomy device 600.

[0098] The tubular body 602 preferably has an elongate central lumen. Anaxially movable flexible drive shaft 608 is provided within centrallumen. In some embodiments, the tubular body 602 may also contain alumen for slideably receiving a guidewire, over which the atherectomydevice 600 may slide to access a body site.

[0099] The atherectomy end 650 of the atherectomy device 600 is shown inmore detail in FIG. 14. A cylindrical sleeve 612 having a central lumen614 surrounds a cutting element 610. The flexible drive shaft 608 isattached to the cutting element 610. The cylindrical sleeve 612 isattached to tubular body 602. The cutting element 610 can have anyconfiguration as known to those of skill in the art. In someembodiments, the cutting element 610 can include a plurality of blades611. The atherectomy device 600 may include a vacuum (FIG. 13) tocollect the material cut by the cutting element 600.

[0100] The cutting element 610 is axially movable such that the cuttingelement is within the sleeve 612 during delivery to the vessel site, andcan be distally extended outside of the sleeve 612 at the vessel site.Accordingly, intermediary vessels are not harmed in delivery of theatherectomy device 600 to the vessel site.

[0101] It is also envisioned that the atherectomy device 600 can bearranged such that the tubular body 602 and cutting sleeve 612 areaxially movable, such that the tubular body and cutting sleeve 612 areproximally retracted to expose cutting element 610.

[0102] In one embodiment, as shown in FIG. 13, the tubular body 602 maybe provided with a central lumen (not shown) for slidably receiving aguidewire 618 to guide the atherectomy device 600 to the vessel site.The cutting element 610 may also include a central lumen (not shown) insuch a configuration.

[0103] A method of using the atherectomy device 600 is illustrated inFIGS. 16A and 16B. FIG. 16A shows the atherectomy end having a tubularbody 602 and cutting sleeve 612 being delivered to a vessel 620 having astenosis 622. FIG. 16B shows the cutting element 610 extending distallyfrom the cutting sleeve 612 to cut and remove the stenosis 622. In someembodiments, the entire diseased portion of the vessel may be removed.In other embodiments, only the stenosis 622 or a portion of the stenosis622 is removed. The vacuum may be used to extract the debris from thetreatment site before removal of the atherectomy device.

[0104] In another embodiment, the motive force for the blade may beprovided by the vacuum and/or an irrigation port. An example of analternative embodiment where such a propulsion system may be provided isdepicted in FIG. 16C and 16D. An atherectomy end 670 has a drill bitstyle cutter 672. Advantageously, this cutter has influent port 674advantageously coupled to the vacuum and/or effluent port 676 forirrigation. The effluent port 676 is coupled to an irrigation lumen. Theinfluent port 674 may advantageously be moved proximally or distally onthe cutter 672 during manufacturing for optimization for different typesof debris removal. Advantageously, either or both of the ports 674, 676could provide propulsion by providing a directional jet or suction port.

Re-impregnation Catheter

[0105] A method of re-impregnating, administering a drug on a deployedstent, or delivering an agent to a lesion or stenosis is also provided.A drug delivery catheter 700 is shown in FIG. 17A and 17B. Deliverycatheter 700 preferably includes an elongate, flexible tubular shaft704, having a proximal end 706 and a distal end 708. The shaft 704defines one or more passages or lumens extending through the shaft.

[0106] Catheter 700 preferably comprises a balloon 714, having aproximal end 716 and a distal end 718. Elongate shaft 704 preferablyincludes a guide wire 722, extending from distal end 716 throughproximal end 706 of shaft 704, providing rigidity to device 700.Catheter 700 also includes a manifold 724. Manifold 724 preferablyincludes a guide wire port 726 and an inflation port 728. Catheter 700may also include radiopaque markers 729 to view the location of catheter700 within the patient's body lumen. Catheter 700 may also include asoft, flexible distal tip 727. Such catheters are known.

[0107]FIG. 17B illustrates a view of the magnified distal end 718 of theballoon 714. A guide wire lumen 730 is depicted. The guide wire lumen730 is adapted to receive an elongate guide wire in a sliding fashionthrough proximal guide wire port 726 (FIG. 17A) in catheter manifold724.

[0108] Preferably, an inflation lumen is connected to the balloon 714 toselectively inflate it with the inflating fluid. The inflation lumenprovides fluid communication between the interior of the balloon 714 andthe inflation port 728 located at manifold 724. The inflation lumen mayalso be adapted to hook up to a vacuum, to eliminate air bubbles.Alternatively, a separate lumen may be provided for connection with thevacuum.

[0109] The catheter shaft 704 may have various configurations other thanthe coaxial design shown in the drawings, including a single extrudedmulti-lumen tube defining any suitable number of colinear or radiallyaligned lumens.

[0110] The balloon 714 may comprise any known balloon configurations.

[0111] In one embodiment, the balloon 714 includes a first balloonelement 734 and a second element 736, each having an associated needleelement 738 and 740, respectively. The needle elements 738 and 740 havea pointed end 746 and include an inner lumen, which is used to deliverat least one therapeutic agent. Any therapeutic agent, such as thosediscussed above, may be used. The pointed ends 746 may be used to cutinto bodily tissue or to contact an indwelling stent. When the balloonis expanded, the needle elements 738 and 740 are pushed outwardly. Theneedles can be advanced distally to impregnate an already deployed stentor medicate bodily tissue with the at least one therapeutic agent uponballoon expansion and contact with the stent or bodily tissue.

[0112] The catheter manifold 724 provides a maneuvering handle for thehealth care professional, as well as an inflation port 728 and a guidewire port 726. Either or both the inflation port 728 or the guide wireport 726 may have a coupling, accompanied by a luer-lock fitting forconnecting an inflation lumen to a source of pressurized fluid in aconventional manner. The manifold 724 may also include an injection portfor allowing radiopaque contrast fluid to be injected through the outersleeve and around the catheter shaft, thus illuminating the deliverydevice on a fluoroscope. The proximal manifold 724 is preferablyinjection molded of any suitable material. A precision gasket may alsobe provided, which seals securely around the device, prohibiting fluidloss. Many other catheter configurations are also known.

[0113] The size of balloon 714 varies, depending on the particulartreatment and access site. The overall length and diameter may varybased on the treatment. In a preferred embodiment, balloon 714 has aninflated length between about 1 and 10 cm, preferably about 4 cm. In apreferred embodiment, balloon 714 has an inflated diameter between about0.1 and 1.5 cm. However, balloons of any dimensions may be used.

[0114] Catheter manufacturing techniques are generally known in the art,including extrusion and coextrusion, coating, adhesives, and molding.The disclosed catheter is preferably made in a conventional manner. Theelongate shaft of the catheter is preferably extruded. The elongateshaft is preferably made of a polymer such as Nylon, the stiffness ofwhich may be selected as appropriate. Material selection varies based onthe desired characteristics. The joints are preferably bonded.Biocompatible adhesives are preferably used to bond the joints. Theballoon is also preferably made in a conventional manner. However, otherconfigurations are also acceptable.

[0115] As shown in FIGS. 18A and 18B, the drug delivery catheter 700 isshown in use. FIG. 18A shows a body vessel 770 having a stenosis 772,and a stent 134, 434 deployed within the body vessel 770. Theimpregnation catheter 700 is shown in the body vessel. FIG. 18B showsthe drug impregnation catheter medicating the stenotic region in thebody vessel 770. The balloon 714 is expanded, such that balloon element734 and balloon element 736 contact different portions of the stent 134,434. The needle elements 738 and 740 bear upward via the balloonelements 734 and 736 into the stenosis 772. A treatment agent isdelivered to the stenosis 772 through the needle elements 738 and 740.

[0116]FIG. 18C depicts an alternative embodiment of the drug deliverycatheter. In this embodiment, needle elements 760 are pre-biasedoutward. They are maintained in a sheeth 712 until they are advanced tothe lesion 772. Then the needle elements 760 are advanced out of thesheeth 712, and due to the bias, can enter or bear on the lesion 772.The needles may also deliver radiopaque material.

[0117] Improved Lesion Mapping

[0118] In a further embodiment, the catheter 700 of FIG. 17A does notcarry needles, but is provided for better mapping of vascular lesions.Preferably, the balloon is made of a very thin membrane. The balloon 714membrane would be thin enough that when gently inflated, in a lesion, itconforms to the lesion topography. The inflation medium is radiopaque,so that with the balloon 714 inflated, the precise contours of thelesion would be visible on X-ray. This embodiment provides animprovement over conventional angiograms, where the radiopaque diesflows through the arteries, and the mapping is imprecise. The balloon714, when embodied in this fashion, is inflated slowly and at lowpressure, just to bear on the lesion and conform to the lesion formapping through radiopaque techniques. Advantageously, the catheter alsopermits blood flow past the balloon during the procedure usingconstructions that provide such blood flow as are known in the art, suchas in U.S. Pat. No. 4,581,017. In addition to improved mapping, such aballoon is advantageous for angioplasty procedures of small or tortuousvessels, where conventional, relatively stiff catheters cannot bemanipulated.

Method

[0119] With reference to FIGS. 19-24, one method of inhibitingrestenosis in accordance with the present invention is shown.

[0120] In accordance with one embodiment a method of delivering a stentof the present invention is shown. As previously discussedself-expanding and balloon expanding stents may be used. A deliverysystem for balloon expanding stents, and a delivery system forself-expanding stents have also been described herein. Tubular graftstents may be used with either self-expanding or balloon-expandingsystems.

[0121] In either system, the delivery system is preferablypercutaneously delivered to the treatment site. The stent ispercutaneously introduced in the contracted condition, advanced to atreatment site within a body vessel, and deployed to assume an enlargedcondition and repair and/or bypass the treatment site.

[0122] A method of delivering a stent system as described abovegenerally includes locating the site to be treated, providing a suitabledelivery catheter, positioning the distal portion of a delivery catheterwith a stent disposed thereon or therein in the branch of the site to betreated, partially deploying the stent in a vessel, adjusting theposition of the stent if necessary, and then fully deploying the stent.Methods of navigating catheters through blood vessels or other fluidconduits within the human body are well known, and will therefore not bediscussed herein.

[0123] In order to visualize the position of a partially orfully-deployed stent with a suitable radiographic apparatus, a contrastmedia may be introduced through the catheter to the region of the stentplacement. Many suitable contrast media are known to those skilled inthe art. The contrast media may be introduced at any stage of thedeployment of the stent system. For example, a contrast media may beintroduced after partially deploying the stent, or after fully deployingthe stent.

[0124] With respect to the balloon expanding delivery system 800 asshown in FIGS. 19-21, a method frequently described for delivering astent to a desired intraluminal location includes mounting theexpandable stent 802 on an expandable member 804, such as a balloon,provided on the distal end 806 of a catheter 808, advancing the catheterto the desired location 810 within the patient's body lumen 812 (FIG.19), inflating the balloon 804 (FIG. 20) on the catheter 800 to expandthe stent 802 into a permanent expanded condition and then deflating theballoon 804 and removing the catheter 800. When fully deployed andimplanted, as shown in FIG. 21, stent 802 will support and hold openstenosed region 810 so that blood flow is not restricted.

[0125] With respect to the self-expanding delivery system 900 as shownin FIGS. 22-24, self-expanding stent 902 is implanted in stenosed region910 by moving outer member 906 in a proximal direction whilesimultaneously moving inner member 908 in a distal direction (FIG. 22).With reference to FIG. 23, as portions of self-expanding stent 902 areno longer contained by outer member 906, it will expand radiallyoutwardly into contact with vessel wall 912 in the area of stenosedregion 910. When fully deployed and implanted, as shown in FIG. 24,stent 902 will support and hold open stenosed region 910 so that bloodflow is not restricted.

[0126] In accordance with another aspect of the present invention,atherectomy may be performed at the treatment site prior to stentdelivery. The atherectomy may be performed using known chemicalatherectomy solutions. Alternatively, the atherectomy may be performedusing an atherectomy device. Preferably, the atherectomy device includesa protective housing member, as described above with reference to FIGS.13-16, to prevent injury to non-diseased vessels, but can be extendedfrom the housing for treatment.

[0127] In accordance with another aspect of the present invention, astent may be impregnated with a therapeutic agent after stentdeployment. As described above with reference to FIGS. 17-18, a catheterhaving a balloon mounted at its distal end may be delivered to atreatment area having a deployed stent. The balloon comprises needleelements including at least one therapeutic agent, which impregnate intoa stent or bodily tissue when the balloon is expanded, contacts thestent, and the needle elements are deployed.

[0128] In accordance with another aspect of the present invention, adirectional catheter may be used to access the treatment site viaguidewire. As described above with reference to FIGS. 11 and 12, thedirectional catheter is delivered to a bifurcated vessel to guide theguidewire to a smaller branch of the vessel, thereby reducing injury tothe vessels.

[0129]FIG. 25 illustrates a multi-balloon catheter 1000 design forinspection or treatment of body lumen. The catheter has two balloons1010, 1020, in this embodiment. Each is inflatable through an inflationport 1030, 1040 that provides fluid communication to an inflation lumenin the catheter shaft. Preferably, this catheter also permits blood flowpast the balloons, in a manner known in the art. For this purpose,influent perfusion ports 1050 and effluent perfustion ports 1052 areprovided. Between the balloons is positioned a camera or lens 1060 forobservation and inspection of a lumen. This lens 1060 may be coupled toa fiber optic to transmit the optical properties to a camera at theproximal end of the catheter 1000, or it may be a CCD viewer or the liketo provide electrical signals with an image. The catheter 1000 may alsoinclude an ultrasound device 1062, such as an intravascular ultrasound(IVUS). Preferably, also positioned between the balloons are one or morefluid ports 1064. Advantageously a suction port 1064 and an infusionport (not shown) are provided. These ports permit removal of bloodbetween the balloons, and infusion with a more transparent medium,through which optical images may be made. Alternatively, a radiopaquematerial may be infused and held in the regions between the balloons,with the lumen sealed by the balloons, so as to obtain more precisemapping through radiographic techniques.

[0130] The foregoing description details certain embodiments of theinventions. It will be appreciated, however, that no matter how detailedthe foregoing appears in text, the inventions can be practiced in manyways. As is also stated above, it should be noted that the use ofparticular terminology when describing certain features or aspects ofthe inventions should not be taken to imply that the terminology isbeing re-defined herein to be restricted to including any specificcharacteristics of the features or aspects of the invention with whichthat terminology is associated. The scope of the invention shouldtherefore be construed in accordance with the ordinary and customarymeaning of the appended claims and any equivalents thereof.

What is claimed is:
 1. A stent comprising: a tubular member having aproximal end, a distal end, and a center portion, wherein the diameterof the proximal end and the diameter of the distal end are greater thanthe diameter of the center portion.
 2. The stent of claim 1, wherein thestent is long enough such that the distal end and proximal end eachextend about 1-6 mm beyond the stenosis.
 3. The stent of claim 1,wherein the distal end and proximal end each extend about 5 mm beyondthe stenosis.
 4. The stent of claim 1, wherein the distal end andproximal end each extend at least 1 mm beyond the stenosis.
 5. The stentof claim 1, wherein the stent is self-expanding.
 6. The stent of claim1, wherein the stent is expanded by a balloon.
 7. The stent of claim 1,further comprising at least one drug.
 8. The stent of claim 1, furthercomprising a plurality of drugs.
 9. The stent of claim 8, wherein atleast one of the plurality of drugs is a time-released drug.
 10. Thestent of claim 1, wherein the diameter of the proximal end is equal tothe diameter of the distal end.
 11. The stent of claim 1, wherein thediameter of the proximal end is greater than the diameter of the distalend.
 12. The stent of claim 1, wherein the diameter of the distal end isgreater than the diameter of the proximal end.
 13. An atherectomydevice, comprising: an axially movable cutting element; and a tubularhousing surrounding said cutting element to protect undamaged vesselsfrom the cutting element.
 14. A catheter placement device comprising: aguidewire; a directional catheter element for directing the guidewire ata bifurcated vessel, wherein the bifurcated vessel comprises a firstmain vessel and a second vessel, wherein said guiding catheter elementis adapted to be delivered over the guidewire and has a diameter at afirst end corresponding to the first main vessel and a diameter at asecond end corresponding to the second vessel, such that the guidewireis directed from the main vessel to the second vessel via the guidingcatheter element; and a balloon for stabilizing the directional catheterelement at the bifurcated vessel.
 15. A method of inhibiting restenosiscomprising: performing atherectomy at a vessel site; and delivering astent to the site, wherein the stent comprises a tubular body having aproximal end, a center portion, and a distal end, said proximal end anddistal end having a larger diameter than said center portion such thatthe stent contains a stenosis.
 16. A method of inhibiting restenosiscomprising: delivering a stent to a treatment site; and impregnating thestent with at least one drug at the treatment site.
 17. The method ofclaim 16, wherein the stent is impregnated about 3-6 months after thestent is delivered to the treatment site.
 18. The method of claim 16,wherein the stent has a collagen sponge to accept the drug.
 19. Themethod of claim 16, wherein said delivering a stent and saidimpregnating the stent are performed with a substantial time between thetwo steps.
 20. A drug impregnation catheter comprising: an elongatetubular body having a proximal end and a distal end; and a balloonattached to the distal end of the tubular body, wherein said ballooncomprises at least one needle element, wherein said needle element isconfigured to deliver a drug to a treatment site.
 21. A stent deliverycatheter comprising: an elongate tubular body having a proximal end anda distal end; and a balloon attached to the distal end of the tubularbody, wherein said balloon comprises a distal portion, a proximalportion, and a center, wherein the diameter of the proximal portion andthe diameter of the distal portion are greater than the diameter of thecenter portion.
 22. A mapping balloon catheter comprising: an elongatecatheter shaft having a distal end; a balloon mounted on said cathetershaft, wherein said balloon is constructed of a material that issufficiently compliant so that when pressure is applied to the inside ofthe balloon to inflate the balloon, the balloon conforms to a stenoticregion.
 23. The mapping balloon of claim 22, wherein the mapping balloonis in fluid communication with an inflation lumen in said cathetershaft, said inflation lumen carrying an inflation medium, wherein theinflation medium is radiopaque.
 24. An inspection catheter for use inbody lumen comprising: an elongate catheter shaft; a first balloon and asecond balloon mounted at spaced locations along said catheter shaft; aoptical inspection element positioned on said catheter shaft between thefirst and second balloons.
 25. The inspection catheter of claim 24,wherein said optical inspection element comprises a lens coupled to afiber-optic in said catheter shaft.
 26. The inspection catheter of claim24, wherein said optical inspection element comprises a CCD.